It is well known to use an annular gasket between mated male and female pipe end sections to form a fluid-tight seal. In most applications, the annular elastomeric gasket is disposed around the end of the male pipe section. In many applications, the gasket is seated in an annular groove that extends around the end of the male pipe section. See, for example, U.S. patent application Ser. No. 10/037,219, for a PIPE HAVING WATERTIGHT INLINE BELL, filed Nov. 9, 2001.
In ground water drainage systems, corrugated pipe of various diameters are used. Sections of such pipe are joined by mating a female end or bell, and a male end or spigot. As with any fluid conveyance piping system, proper sealing at the joined ends is necessary. Unlike many piping systems, corrugated pipe used for ground water drainage is subjected to numerous stresses during installation and use that must be accommodated by any annular gasket disposed between bell and spigot.
During mating of the pipe sections, a gasket is disposed around the end of the spigot. Due to contact with the bell during the mating, the gasket is subjected to forces tending to displace (e.g., roll) the gasket relative to the spigot. Even if the gasket is seated in an annual groove, the forces acting on the gasket during mating of spigot and bell may dislodge the gasket from the groove.
During use, a corrugated pipe system is subjected to inward pressure from the soil and rocks surrounding the pipe system, to outward pressure from fluid flowing through the pipe system, and to pressure from ground water in the soil that acts externally on the pipe system. These forces cause the pipe sections to flex axially and radially. Such movement requires a gasket that can accommodate variations in distance between bell and spigot, relative movement between bell and spigot, and infiltration of ground water tending to move the gasket relative to the bell and spigot.
The gasket disclosed and claimed herein, while having application in various pipe systems, is particularly effective in resisting the various forces that impact on ground water drainage systems, such as those comprising corrugated pipes. In addition, the gasket provides a sufficient sealing range to accommodate manufacturing tolerances. Further, the gasket provides a cost-effective design by providing sufficient sealing while minimizing the amount of material needed for the gasket. Additional advantages of the invention are set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention.